How does the metal material liquid cooling oxygen-free copper achieve near-theoretical thermal conductivity efficiency in liquid cooling systems?
Publish Time: 2025-10-02
Liquid cooling technology has become a mainstream heat dissipation solution due to its efficient heat exchange capabilities. As the core thermal conductivity material in liquid cooling systems, liquid cooling oxygen-free copper, thanks to its excellent physical properties, achieves near-theoretical thermal conductivity efficiency, making it the material of choice for high-end heat sinks, cold plates, and cooling pipes.1. High Purity for Excellent Thermal ConductivityLiquid cooling oxygen-free copper is an extremely pure electrolytic copper. Its most significant feature is its extremely low oxygen content, typically controlled below 10 ppm. This high purity fundamentally eliminates the cuprous oxide inclusions common in traditional copper materials. These tiny oxides not only scatter electrons, hindering heat transfer, but also act as a source of thermal resistance, reducing overall thermal conductivity. In metals, heat conduction primarily relies on the movement of free electrons. Liquid cooling oxygen-free copper, with its minimal impurities and complete lattice structure, offers a longer mean free path for electrons and a lower scattering probability. This allows it to quickly remove more heat from the heat source per unit time, significantly improving the response speed and heat dissipation capacity of the liquid cooling system.2. Microstructural Optimization of Heat Flow PathsLiquid cooling oxygen-free copper components in modern liquid cooling systems, such as cold plates, cold heads, and microchannel heat sinks, are typically manufactured using precision machining or welding processes. Liquid cooling oxygen-free copper's excellent ductility and machinability enable it to be fabricated into complex microchannel structures with channel widths as small as 0.2 mm, significantly increasing the contact area between the coolant and the metal and enhancing convective heat transfer. More importantly, liquid cooling oxygen-free copper's uniform and dense grain structure, with few internal defects, allows for virtually unimpeded heat flow within the material, creating a continuous, low-resistance thermal path. This uninterrupted heat conduction path ensures rapid and uniform heat transfer from heat sources like CPUs and IGBT modules to the coolant, preventing the formation of localized hot spots and improving overall system thermal management efficiency.3. Surface Quality and Contact Thermal Resistance ControlIn liquid cooling systems, the interface between the liquid cooling oxygen-free copper (LCOF) and the heat source is a critical link in heat transfer. The flatness, roughness, and degree of oxidation of the contact surface directly impact the contact thermal resistance. After precision grinding or electrochemical polishing, the surface roughness of LCOF copper can be controlled to below Ra 0.2μm, ensuring close contact with the chip surface over a large area. Furthermore, because LCOF copper is kept in an inert atmosphere or vacuum during manufacturing and use, it is less susceptible to the formation of an oxide layer on its surface. Ordinary copper, in contrast, quickly forms a copper oxide film with extremely poor thermal conductivity when exposed to air, significantly increasing the interfacial thermal resistance. The "clean" surface of LCOF copper effectively reduces the contact thermal resistance, enabling efficient heat transfer across the interface.4. Long-term Stability Ensures Consistent and Efficient Thermal ConductivityMaterial thermal stability is crucial for the long-term operation of liquid cooling systems. LCOF copper exhibits excellent resistance to thermal fatigue and is less susceptible to cracking or deformation during repeated thermal expansion and contraction cycles. Its high corrosion resistance also ensures long-term use in deionized water or specialized coolant environments without electrochemical corrosion or deposition, maintaining long-term stable thermal conductivity. Furthermore, liquid cooling oxygen-free copper exhibits excellent compatibility with common liquid cooling fluids (such as water and ethylene glycol mixtures), preventing chemical reactions and the formation of precipitates that could affect heat transfer, ensuring unobstructed cooling channels.The ability of liquid cooling oxygen-free copper to achieve near-theoretical thermal conductivity efficiency in liquid cooling systems stems from its high purity, low impurity content, dense grain size, and excellent processability. It not only possesses the inherent high thermal conductivity of copper but also minimizes various losses during heat transfer by eliminating oxide defects, optimizing the microstructure, and improving surface quality. In modern technological applications that pursue extreme heat dissipation performance, liquid cooling oxygen-free copper has become a "superconducting bridge" connecting heat sources and cooling media, providing an irreplaceable material guarantee for the stable operation of high-power electronic devices.
